Cranial sutures ​

Cranial sutures Definition

Cranial sutures are fibrous tissue bands that join the skull bones. The complex, windy lines of such thin cranial suture lines mark the joining between the closure and growth of the cranial fontanelles and the bones.

People often wonder the cranial sutures begin to form at about what age? These shallow grooves, which might appear as fractures to lay people, are actually joints made of fibrous, strong tissue that hold together the bones of the skull of a baby until about 2 years of age when the bones fuse. Until this age, the sutures are found to intersect at the soft spots on the head or the fontanels.

Cranial sutures Anatomy​

Some of these structures extend to the forehead, whereas others move to the back and the sides of the skull. A suture in the middle part of the skull extends to the back of the head from the front section. In the skull, the major sutures comprise of:​

Lambdoid suture – It extends across the rear part of the head. Every plate of the parietal bone plate connects with the plate of the occipital bone at the lambdoid suture.

Sagittal suture – It extends from the front to the back section of the head, and down the mid section of the top area of the head. It is at this suture that the two plates of the parietal bone connect.

Coronal suture – It extends from one ear to another. At the coronal suture, every plate of the frontal bone connects with a parietal bone plate.

Metopic suture – It extends from the top part of the head to the nose down the mid section of the forehead. It is at the metopic suture that the two frontal bone plates connect.

Cranial sutures Function​

The skull of an infant is constituted of 6 isolated skull or cranial bones, Frontal bone, Occipital bone, two temporal bones and two parietal bones. The sutures hold these bones together.

The fontanelles and sutures are necessary for the growth and development of the infantile brain. When a child is born, the infant cranial sutures are flexible enough to let the bones overlap so that the infant’s head can move easily through the birth canal without the drain being pressed on and damaged.

The sutures are flexible during infancy and childhood, and let the brain grow fast. These also keep the brain protected from small impacts to the head – as happens when an infant is just learning to hold up his head, sit up or roll over. The brain of a child cannot grow sufficiently and might suffer damage without fontanelles and flexible sutures.

Physicians feel the fontanelles and cranial sutures to follow the growth and development of a child. When they feel the tension of the fontanelles, they are capable of assessing the pressure within the brain.

During the birth process, the bones get the chance to move freely due to sutures. These act similar to an expansion joint, and let the bone get uniform enlargement while the brain enlarges and the skull becomes larger, allowing the head to get a symmetrical shape. However, in case of premature cranial sutures closure, the area will not witness any growth. Premature closure of cranial sutures can compel growth in some other area, making the head shape abnormal.

Cranial sutures Diagrams ​

The following Cranial sutures pictures and images allow a glimpse into the structure.